Chapter 3: Services
In This Chapter
Running code without bothering the user
Running code when a device starts
Starting, binding, and querying
Sending messages from one process to another
Some things are of no concern to the user of an Android device. “A process on your phone is checking for e-mail right now . . . Nope, no new e-mail. Sorry about the interruption. Get back to what you were doing. You’ll hear from me again in exactly one minute.” Such notices are intrusive and unnecessary, especially on a device with limited screen real estate.
To do something behind the scenes, you don’t want an Android activity. An activity normally has a layout file, and the user deals with the layout’s gizmos on the screen. Instead, you want the kind of component that runs quietly in the background. In other words, you want an Android service.
A Very Simple Service
I start this chapter with an embarrassingly simple example — a service that doesn’t do anything. This lazy service simply illustrates the minimum service source code requirements.
The service
Listing 3-1 contains the good-for-nothing ...
